Worksheet on blood type genetics, covering multiple allele traits and inheritance patterns.

Genetics: Multiple Allele Traits - Blood Type

Blood type is controlled by three alleles: A, B, and O. The alleles A and B are codominant, while O is recessive. Here's how the blood types are determined:
- Type A: Genotypes AA or AO
- Type B: Genotypes BB or BO
- Type AB: Genotype AB (codominance of A and B)
- Type O: Genotype OO

Let's solve each question step by step.

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1.

#### a) What are the two genotypes possible for a person who has A blood?
- Answer: AA, AO

#### b) What genotype does a person with AB blood have?
- Answer: AB

#### c) What genotype does a person with O blood have?
- Answer: OO

#### d) What are the two genotypes possible for a person who has B blood?
- Answer: BB, BO

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2.

A man with type AB blood (genotype AB) is married to a woman also with type AB blood (genotype AB). What percentage of their children will have:
- A blood?
- Possible genotypes from AB × AB: AA, AB, BA, BB
- Only AA results in type A blood.
- Probability = 1/4 = 25%

- B blood?
- Possible genotypes from AB × AB: AA, AB, BA, BB
- Only BB results in type B blood.
- Probability = 1/4 = 25%

- O blood?
- Possible genotypes from AB × AB: AA, AB, BA, BB
- No OO can be formed.
- Probability = 0%

- AB blood?
- Possible genotypes from AB × AB: AA, AB, BA, BB
- Both AB and BA result in type AB blood.
- Probability = 2/4 = 50%

Final Answer:
- A blood: 25%
- B blood: 25%
- O blood: 0%
- AB blood: 50%

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3.

A man has type B blood (genotype BB) and is married to a woman with type O blood (genotype OO). What blood type will all their children have? What is the genotype of the children?
- Possible genotypes from BB × OO:
- All offspring will inherit one B allele from the father and one O allele from the mother.
- Genotype of all children: BO
- Blood type of all children: B

Final Answer:
- Blood type: B
- Genotype: BO

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4.

A woman with type A blood (genotype AO) is married to a type B person (genotype BO). What proportion of their children will have:
- A blood?
- Possible genotypes from AO × BO: AB, AO, BO, OO
- Only AO results in type A blood.
- Probability = 1/4 = 25%

- B blood?
- Possible genotypes from AO × BO: AB, AO, BO, OO
- Only BO results in type B blood.
- Probability = 1/4 = 25%

- O blood?
- Possible genotypes from AO × BO: AB, AO, BO, OO
- Only OO results in type O blood.
- Probability = 1/4 = 25%

- AB blood?
- Possible genotypes from AO × BO: AB, AO, BO, OO
- Only AB results in type AB blood.
- Probability = 1/4 = 25%

Final Answer:
- A blood: 25%
- B blood: 25%
- O blood: 25%
- AB blood: 25%

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5.

A woman with type A blood is claiming that a man with type AB blood is the father of her child who is type B. Could this man be the father of the child? Show the possible crosses; remember that the woman can have AA or AO genotypes.

#### Case 1: Woman is AA (type A)
- Possible genotypes from AA × AB: AB, AB
- All offspring will have type AB blood.
- Not possible for the child to have type B blood.

#### Case 2: Woman is AO (type A)
- Possible genotypes from AO × AB: AA, AO, AB, BO
- Offspring can have type B blood if they inherit the B allele from the father and the O allele from the mother.
- Possible for the child to have type B blood.

If the man is the father, what must the mother's genotype be?
- The mother must be AO to allow the child to inherit the O allele and express type B blood.

Final Answer:
- Could this man be the father? Yes
- Mother's genotype: AO

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6.

A man with type AB blood is married to a woman with type O blood. They have two natural children and one adopted child. Jane has type A blood, Bobby has type B blood, and Grace has type O blood. Which child was adopted?

#### Analysis:
- Man: AB (genotype AB)
- Woman: O (genotype OO)

Possible genotypes from AB × OO:
- AO (type A)
- BO (type B)

From this, we see:
- Natural children can only have type A (AO) or type B (BO).
- Type O (OO) is not possible because the father cannot contribute an O allele.

Since Grace has type O blood, she cannot be a natural child. Therefore, Grace must be the adopted child.

Final Answer:
- Adopted child: Grace

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Summary of Answers:

1. a) AA, AO
b) AB
c) OO
d) BB, BO

2. A blood: 25%, B blood: 25%, O blood: 0%, AB blood: 50%

3. Blood type: B, Genotype: BO

4. A blood: 25%, B blood: 25%, O blood: 25%, AB blood: 25%

5. Could this man be the father? Yes, Mother's genotype: AO

6. Adopted child: Grace

Final Boxed Answers:
\[
\boxed{
\begin{array}{l}
1. \text{a) AA, AO} \\
\text{b) AB} \\
\text{c) OO} \\
\text{d) BB, BO} \\
2. \text{A blood: 25%, B blood: 25%, O blood: 0%, AB blood: 50%} \\
3. \text{Blood type: B, Genotype: BO} \\
4. \text{A blood: 25%, B blood: 25%, O blood: 25%, AB blood: 25%} \\
5. \text{Yes, AO} \\
6. \text{Grace}
\end{array}
}
\]